I feel like a jerk mentioning this, but I assume that Huntress is the official in charge of the school, and not the guiding method for how they model their teaching methods.
(The easy trick to dealing which one is principal and which one is principle is to remember that the "Principal is your pal", and thus a human being rather than an abstract idea.)
Of course, now people will come and try to explain how a school whose guiding principle is Helena Bertinelli would actually work.